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Science > Physics || Electricity > Flashcards

Physics || Electricity Flashcards

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1
Q

Formula For Charge?

A

Charge
= Current x Time

   Q
I      T    (QUIT)
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2
Q

Formula For Resistance?

A

Resistance
= Voltage / Current

V
I R

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3
Q

Formula For Energy?

A

Energy
= Voltage x Charge

E V      Q
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4
Q

Potential Difference Is?

A

(Another word for Voltage),

The difference is energy before and after they have carried though a component.

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5
Q

Easier Current Found?

A

The wire with the highest resistance is the easiest route in a wire because most of the current has took that way.

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6
Q

Origin?

A

(0,0) on the graph.

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7
Q

3 Formula Using Power?

A

P
I V
(Power, Current, Voltage).

E
P T
(Energy, Power, Time).

P
I2 R
(Power, Current ((Squared)), Resistance).

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8
Q

Current Is Measured In?

A

Amps.

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9
Q

Energy Is Measured In?

A

Joules.

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10
Q

Charge Is Measured In?

A

Coulombs.

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11
Q

Resistance Is Measured In?

A

Ohms.

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12
Q

Power Is Measured In?

A

Watts.

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13
Q

Voltage Is Measured In?

A

Volts.

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14
Q

Current And Voltage In A Series Circuit?

A

Current in a series circuit is the same, voltage adds.

Current in a parallel circuit adds, voltage same.

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15
Q

Current And Voltage In A Metal Wire?

A

Current and Voltage are directly proportional,

Increase’s in a straight line.

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16
Q

Current + Voltage In A Diode?

A

Reaches >1.5 then straits to conduct electricity,
Symbol for diode is >| with circle surrounding it,

Current only flows through diode in one direction,

Diode has very high resistance in opposite direction.

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17
Q

Current And Voltage In A Bulb?

A

As current increases, voltage increases too but gradually slows down as resistance increases,
Gradual curve on graph,
Current gets bigger because bulb is giving off energy (heat and light).

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18
Q

Current And Voltage In A Resistor?

A

Resistor symbol is a rectangle on a wire,

Current and voltage increases straight up.

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19
Q

Current And Voltage In An LDR?

A

LDR symbol is a rectangle with a circle surrounding it and two arrows pointing toward the circle,
The resistance starts at the top left and decreases to bottom right,
When light intensity is high (light), resistance is low and current is high,
When light intensity is low (dark), resistance is high and current is low.

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20
Q

Variable Resistor?

A

Rectangle with a arrow going through it symbol,

Resistance always goes up the side on a graph.

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21
Q

Current And Voltage In A Thermistor?

A

Thermistor symbol is a resistor with a flat line beneath is that goes through it,
Resistance is the same as LDR,
Higher temperature = Lower resistance.

22
Q

Voltmeter Measures?

A

Voltage.

23
Q

Amp-Meter Measures?

A

Current.

24
Q

Conventional Current Flow?

A

Positive to Negative.

25
Q

Two Resistors In A Series Circuit?

A

Resistance adds together.

26
Q

Two Resistors In A Parallel Circuit?

A

Less resistance in bot resistors than there was before,

This happens because current has two paths to go through.

27
Q

Symbol Difference Of A Battery And A Cell?

A

Cell is just one battery symbol,

Battery is two battery symbols.

28
Q

Lamp Symbol?

A

Circle with a cross.

29
Q

Formula For Work Done?

A

Work Done = Force x Distance

30
Q

Why Does Resistance Increase With Temperature?

A

Electrons collide with ions in the lattice that makes up the resistor,

This give the ions energy which causes them to vibrate and heat up,

The more the ions vibrate, the harder it is for the electrons to get through the resistor because there are more collisions,

This means the current decreases and the resistor heats up,

If resistor gets too hot, current does not flow through it.

31
Q

How Might Someone Investigate Relationship Between Current And Voltage?

A

Connect a circuit with the component your measuring, amp meter, power source and a voltmeter over the resistor,

This is a series circuit and the voltmeter must be parallel,

Change the output potential difference (voltage) of the power supply,

This alters the current flowing through the circuit and the potential difference in the component we are measuring,

Take several readings from amp meter and voltmeter,

Plot the current again the potential difference in an I-V graph,

Use this data to find resistance using R=IV,

Make sure the circuit doesn’t get too hot as this will mess up the experiment.

32
Q

What Do You Always Write About Practicals?

A

Repeat the practical and calculate the means.

33
Q

Ammeters Are Always?

A

Connected in series.

34
Q

Voltmeters Are Always?

A

Connected in parallel.

35
Q

Practical To Investigate Properties?

A

Set a series circuit out with a ammeter, resistor and voltmeter parallel to the resistor. Obviously include a battery too,

Vary the potential difference from the power supply,

Record the readings from the ammeter and voltmeter for each change,

Replace the resistor with a lamp and repeat these steps ^,

Now connect a second filament lamp to the circuit in a parallel to the first,

Connect ammeters and a second voltmeter to the extra parallel circuit so both parts of the circuit are the same,

Again, vary the potential difference of the supply and write form the current and potential difference across the lamp.

36
Q

Two Types Of Electricity Supply?

A

Alternating current and direct current,

A.C. and D.C.

37
Q

A.C. Supply?

A

The current is constantly changing direction,

They are produced by alternating voltages,

Voltage is positive then negative and then positive then negative, etc,

The UK mains id a.c. at around 230 volts,

A.c. frequency in Maine id 50 cycles per second (50 hz).

38
Q

D.C. Current?

A

Batteries and cells are direct currents,

This means the current is always flowing in the same direction and is created by a direct voltage,

Voltage is positive or negative, not both.

39
Q

Live Wire?

A

Brown,

Carries the voltage,

Alternates between a high +ve and -ve of about 230v.

40
Q

Earth Wire?

A

Green Or Yellow,

For safety and protecting wires,

Carries the current away if something goes wrong and stops the appliance casing becoming live,

It’s also 0 volts.

41
Q

Neutral Wire?

A

Blue,

Completes the circuit,

Electricity normally flows in through the live wire and out through the neutral Wire,

Neutral wire is always at 0 volts.

42
Q

Potential Difference Between The Cable Wires?

A

Pd between live and beautiful equals to the supply (so 230v),

Pd between live and easy is also 230v,

No pd between the neutral and the Earth, they’re both at 0v,

Basically, there’s on a pd between the live and another cable.

43
Q

Touching Live Wire?

A

Your body is at 0v,

This means a large potential difference goes through the body when you touch the live wire of 230v,

This causes an electric shock,

Even if it is turned off, the current isn’t flowing but there is still a pd in the live,

We create a low resistance pathway from the live to earth.

44
Q

Earth Is?

A

0 volts,

Just like us, our body’s, we are also 0 volts.

45
Q

How Do Electrical Overloads Happen?

A

Surges in current can occur because of electrical changes in a current or because of a fault in an appliance,

This can cause fires and melting or shocks,

Earth wire and a fuse prevent this from happening.

46
Q

Surge Is?

A

Sudden increase.

47
Q

How To Prevent Electrical Overloads?

A

If live wire touches case, the case is earthed so the current goes into the Earth wire from the case,

The fuse melts when there is a surge in current,

Fuses are connected to live so that breaking the fuse breaks the circuit and cuts of the live supply,

This makes it impossible to get an electric shock from the case and prevents fires.

48
Q

Fuses?

A

Fuses should be rated as near possible but just a bit higher than the normal operating current,

This means if the current increases just a little bit, it will melt and break the circuit.

49
Q

Circuit Breaker?

A

Even safer than fuses,

Instead of melting a fuse, a large current may trip (turn off) a circuit breaker,

Circuit breakers turn off quicker than the time it takes a fuse to melt,

Circuit breakers are more expensive.

50
Q

Double Insulated?

A

All appliances with metal cases and usually earthed to make them safe from shocks,

If the appliance had a plastic casing and no metal parts showing, it is double insulated,

Anything double insulated doesn’t need an Earth wire connected to it, just a live and neutral.

51
Q

Two-Core Cables?

A

Cables that only carry the live and neutral are called Two-Core cables,

They must be double insulated.

52
Q

What Does “Earthed” Mean?

A

It is connected to an Earth Wire and cannot become live,

E.g. casing on a plug is earthed so it cannot give you a shock.

Science (26 decks)

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